Picamilon is a synthetic compound formed by combining niacin (vitamin B3) and gamma-aminobutyric acid (GABA). It was developed in Russia in the 1960s and has been used there as a prescription medication for a variety of neurological conditions. The rationale for its use in “cloudy thinking” (often described as brain fog or cognitive impairment) is primarily based on its purported ability to cross the blood-brain barrier, delivering GABA directly to the brain, and its potential vasodilatory (blood vessel-widening) effects from the niacin component. Some small clinical trials and animal studies have suggested that Picamilon may improve cerebral blood flow and offer mild anxiolytic (anxiety-reducing) and nootropic (cognitive-enhancing) effects. However, the overall quality and quantity of the evidence are limited, with few well-designed, placebo-controlled human studies specific to cognitive clarity or “cloudy thinking.” Most of the data come from Russian-language studies that are not widely accessible or have methodological limitations. Regulatory authorities in countries such as the United States do not recognize Picamilon as a dietary supplement or approved drug. Therefore, while there is some scientific basis and historical use, the strength of evidence for Picamilon’s effectiveness in treating or supporting clear thinking is low (rated 2/5).